JP2003081679A - Moisture absorbing and desorbing material and method of producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a formed product which is obtained by imparting toughness to a hardened body of an amorphous silicate and used as a building material, and to provide a method of producing the same. SOLUTION: A slurry consisting of an amorphous silicate raw material and an aqueous solution of sodium hydroxide is impregnated into a nonwoven base material and then the resulting material is subjected to heat treatment.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel inorganic molded body used for applications such as interior building materials, ceiling materials, humidity control members, dehumidifying members, etc., and a molding method thereof.

[0002]

2. Description of the Related Art With the progress of airtightness of buildings in recent years,
Damages such as the occurrence of dew condensation and the generation of molds and mites due to this dew condensation continue to increase.As a countermeasure against this, the building materials themselves have a moisture absorption and desorption function along with the introduction of forced air conditioning methods by mechanical equipment. However, it is being sought to adjust the indoor humidity by a more passive method. Heretofore, zeolite-based materials, calcium silicate hydrate-based materials, diatomaceous earth-based materials, and silica gel-based materials have been known as moisture absorbing / releasing materials for this purpose. Further, JP-A-9-328374 discloses the same purpose. , There is a description of a cured product obtained by heat-treating perlite with an alkali hydroxide.

The former material must be dispersed in gypsum or the like when it is molded, or must be fired, so that the moisture absorption and desorption property cannot be reduced.

The latter pearlite cured product has practically sufficient strength, light weight, moisture absorption and desorption properties, and has the potential to be an economical material because it can be produced by a relatively simple method. As a drawback, since it is glassy, it is highly brittle and lacks impact resistance, so it was necessary to solve this brittleness in order to use it as a building material.

[0005]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a hardened body obtained by heat-treating an amorphous silicate containing pearlite with sodium hydroxide, to give it toughness, and to use it as a building material. It is to provide the manufacturing method.

[0006]

Means for Solving the Problems The inventors of the present invention impregnated a nonwoven fabric substrate with a slurry comprising an amorphous silicate raw material and sodium hydroxide, and then heat-treated the amorphous silicate raw material. It was found that a moisture-absorbing / releasing porous molded article having excellent toughness can be obtained by introducing a hydrophilic group into the non-woven fabric and bonding the silicate raw materials together in the nonwoven fabric, and completed the present invention.

That is, according to the present invention, a non-woven fabric substrate is impregnated with a slurry composed of an amorphous silicate raw material and sodium hydroxide in a range of 5 to 20 in terms of SiO ₂ / Na ₂ O molar ratio, and then heated. A moisture-absorbing / desorbing porous molded article obtained by treating the amorphous silicate raw material with hydrophilic groups and binding the siliceous raw materials to each other in the nonwoven fabric.

Further, according to the present invention, a nonwoven fabric substrate is impregnated with a slurry comprising the above-mentioned amorphous silicate raw material and sodium hydroxide and then heat treated in a dryer at 80 to 250 ° C. After heat treatment, further 100-200
A method for producing a moisture absorptive and desorptive porous molded article, which comprises performing heat treatment under pressure with a hot press at ℃. Hereinafter, the present invention will be described in detail.

The non-woven fabric substrate referred to in the present invention is a fiber sheet, web or pad of polyethylene, polypropylene, polyester, nylon, vinylon, etc., in which the fibers are unidirectionally or randomly oriented, and by friction, entanglement or adhesion. Fibers are combined, relatively low density and large fiber gaps, and basis weight is 100g-50g
0 g is suitable for use.

As the amorphous silicate raw material, diatomaceous earth, volcanic ash (shirasu), minestone, volcanic vitreous clay, pearlite,
Obsidian, pine rock, and fired foams thereof (perlite, shirasu balloon, etc.) are used, but plate glass, bottle glass and waste glass powder thereof which are generally widely used can also be used. Further, fine silica such as silica fume can be used in accordance with the amorphous silicate raw material. These amorphous silicate raw materials are used after being adjusted to a particle size that can be a slurry.

The quality of sodium hydroxide is not particularly specified. For example, general industrial grade sodium hydroxide is
Before use, dilute it to the required concentration.
Here, part or all of sodium hydroxide may be replaced with potassium hydroxide or lithium hydroxide depending on the desired moisture absorption / desorption characteristics.

According to the present invention, the above amorphous silicate raw material and alkali hydroxide are mixed in an SiO ₂ / Na ₂ O molar ratio of 5 to 2.
A slurry prepared by blending so as to be in the range of 0, and preferably in the range of 8 to 15, is prepared by impregnating the non-woven fabric substrate with this slurry, and then heat-cured in a hot air oven and a hot press.

It is considered that this heat curing reaction proceeds as follows, taking sodium as an alkali as an example. First, at the stage when water is sufficiently present in the initial stage of heating, a part of the siloxane skeleton constituting the amorphous silicate raw material is cleaved by the attack of sodium hydroxide,
A large amount of silanol groups (and their sodium salts) are produced, and a part of the silicate is reduced in molecular weight. When the heating further proceeds to the stage of dehydration reaction, a part of the silanol groups is polymerized again to regenerate the siloxane skeleton and polymerize the silicate again. At this time, the low-molecular-weight silicate acts as a kind of binder, and particles of the silicate raw material are bonded to each other by the polymerization reaction to form a hardened body. In addition, the silanol group (or its sodium salt) formed
Most of them change to a siloxane structure during the polymerization process, but some of them remain as they are, giving the molded article excellent moisture absorption and desorption characteristics.

In the present invention, the SiO ₂ / Na ₂ O molar ratio is set to 2
The amount set to 0 or less is that at least this amount of NaOH is required to produce the required amount of sodium silicate as a binder, and when the compounding amount of NaOH falls below this range, the amount of sodium silicate produced This is because the moisture content is reduced and the sufficient binder effect cannot be exhibited, and at the same time, the moisture absorption / release property is also impaired. On the other hand, the molar ratio of 5 or more means that below that, NaOH remains unreacted and raises the alkalinity of the molded body, and at the same time, lower molecular weight sodium silicate is excessively produced, This is because it impairs water resistance.

Further, in the present invention, it is important that the series of reactions described above is set so as to be carried out via the non-woven fabric substrate. The hardened sodium silicate is brittle and glassy, and a molded body using this as a binder is generally hard and brittle.

In the present invention, the basis weight of the nonwoven fabric substrate is 10
A molded product obtained by impregnating a thin matte non-woven fabric of 0 to 500 g / m ² with 6 to 24 times the weight of the non-woven fabric in terms of solid content and substantially containing 4 to 15% of fibers. By this, it was possible to solve this brittleness and provide excellent flexibility.

The amount of fibers is set in this range, because when the amount of fibers is 4% or less, the reinforcing effect of the fibers cannot be sufficiently exerted.
It cannot solve the brittleness of sodium silicate. Also, 15%
The above is difficult to manufacture, and the effect of fiber reinforcement is saturated, so that it does not make sense to increase the amount of fibers.

In the method for producing a moisture absorptive and desorptive porous molded article of the present invention, an aqueous sodium hydroxide solution is used for an amorphous silicate raw material and SiO ₂ / SiO ₂ for a SiO ₂ in the silicate raw material.
Formulated such that 5 to 20 with Na ₂ O molar ratio, to prepare a slurry agitator. The solid content concentration in the slurry is adjusted so that the nonwoven fabric substrate can be impregnated with a viscosity by adjusting the amount of water. The solid concentration is usually 30 to 6
It is in the range of 0%.

Next, this slurry is transferred to an impregnation tank, the non-woven fabric is dipped into the slurry layer, the non-woven fabric is impregnated with the slurry, and the excess slurry is squeezed out by roll pressing. By this operation, the amount of slurry impregnated into the nonwoven fabric is adjusted. The impregnated amount of the slurry is, in terms of solid content, impregnated with the slurry in an amount of 6 to 24 times the weight of the nonwoven fabric, and substantially 4 to 1
A fiber amount of 5% is desirable.

The non-woven fabric impregnated with the slurry is heated to 80 to 25 by using a batch type hot air dryer or a continuous hot air dryer.
Dehydrate and dry at a temperature of 0 ° C. until it becomes absolutely dry. If the drying temperature is lower than 80 ° C, it takes a long time to dehydrate, and if it exceeds 250 ° C, it is difficult to obtain sufficient strength due to rapid dehydration. By this operation, thickness, 2 to 15 mm, density 0.3 to 0.6 g /
A plate-like body of cm ³ is obtained.

As another method, dehydration drying in a dryer is used as preliminary drying, and the water content of the slurry-impregnated nonwoven fabric is 50 to 50%.
It is also possible to manufacture a plate-like body by drying to a range of 0.1% and then performing a pressure compression treatment with a hot press at 100 to 250 ° C.

In this case, it is possible to further increase the thickness of the compact and the density adjustment width by adjusting the pressing pressure. The thickness is 0.5 to 15 mm and the compact density is 0.3.
It can also be set to 1.2 g / cm ³ . The pressing pressure is not particularly limited, but usually 0.1 to 30 k for practical use.
A pressure of gf / cm ² is used. In addition, a heat-pressing operation using a hot press can provide a molded article having a higher smoothness than that obtained by a dryer alone method.

The molded body obtained by such a manufacturing method is
It has excellent mechanical strength, especially flexibility, and also has excellent moisture absorption and desorption performance.

[0023]

[Example 1] (Production example using a hot air dryer) 90 parts by weight of volcanic glassy white clay (manufactured by Biei Shirato Kogyo) having a SiO ₂ content of 72% and fine powder silica having a SiO ₂ content of 95% (manufactured by Kinseimatic, EFACO) Silica fume) 8.97 wt. A slurry was prepared by adding 111.5 parts by weight of an aqueous NaOH solution having a concentration of 100% and mixing with a universal mixer.

This slurry was transferred to a square-shaped vat, and 50 ×
Nonwoven mat cut to 50 cm (made by Toa Boshoku, olefin-based nonwoven N-12904B, basis weight 250 g / m
² ) Soak and impregnate the slurry, then place on a metal plate,
Excessive slurry was squeezed out by roller pressing to adjust the slurry impregnation amount to prepare a non-woven fabric mat containing about 1,590 g of the slurry.

This slurry-impregnated non-woven mat is heated to 160 ° C.
It was put into the hot air dryer of No. 1 and dried for about 100 minutes until it became completely dry to produce a molded body.

The molded body thus obtained is treated with 50 × 2.
Bending test was carried out by cutting out to 00 mm. Test conditions are centralized loading, span 100 mm, load speed 2 mm / mi
It was set to n. To measure the moisture absorption and desorption performance, the test piece cut out into 50 × 100 mm was placed in a thermo-hygrostat set to repeat the conditions of 25 ° C., 90% RH and 50% RH in a 24-hour cycle. The water content of the test piece was measured every time, and the moisture absorption rate and the moisture release rate were calculated from the measured values.

The measurement results are shown in Table 1. In addition, the load-displacement curve of the bending test is shown in FIG. 1, but it was displaced without breaking even under the load.

[0028]

[Example 2] (Production example in which hot pressing was performed after preliminary drying) S
90 parts by weight of volcanic vitreous clay (manufactured by Biei Shirato Kogyo) having an iO ₂ content of 72% and fine powder silica having an SiO ₂ content of 95% (manufactured by Kinseimatic, EFACO silica fume)
8.70 wt. 1% aqueous NaOH solution
15 parts by weight were added and mixed by a universal mixer to prepare a slurry.

This slurry was transferred to a square vat and 50 ×
Nonwoven mat cut to 50 cm (Toa Boshoku, olefin-based nonwoven TB-165, basis weight 165 g / m ² ).
Was impregnated with the slurry and then placed on a metal plate, and the excess slurry was squeezed out by roller pressing to adjust the slurry impregnation amount to prepare a nonwoven fabric mat containing about 1,130 g of the slurry.

The slurry-impregnated non-woven fabric mat was heated at 160 ° C.
It was put in the hot air dryer of No. 1 and pre-dried for about 50 minutes.
The water content of the slurry-impregnated nonwoven fabric was 4.5%. This pre-dried nonwoven fabric was put into a 160 ° C. hot press equipped with a 4 mm thickness-regulating stopper, and heat-pressed for about 10 minutes to prepare a molded body.

The molded body thus obtained was used in Example 1.
A bending test and a moisture absorption / desorption property test were conducted in the same manner as in, and the results are shown in Table 1.

[0032]

[Example 3] (Production example in which hot-pressing was performed at a relatively high pressure after preliminary drying) A slurry was prepared under the same conditions as in Example 2. Transfer this slurry to a square vat, 50x50c
Non-woven mat cut to m (made by Toa Boshoku, polyester-based non-woven fabric CHINA110MK, basis weight 110g / m
² ) Soak and impregnate the slurry, then place on a metal plate,
Excessive slurry was squeezed out by roller pressing to adjust the slurry impregnation amount to prepare a non-woven mat containing about 690 g of the slurry.

This slurry-impregnated non-woven fabric mat is heated to 160 ° C.
It was put in the hot air dryer of No. 1 and pre-dried for about 30 minutes.
The water content of the slurry-impregnated nonwoven fabric was 5%. Two sheets of this pre-dried non-woven fabric were overlapped, sandwiched between release papers, placed in a heat press at 160 ° C., and heat-pressed at a pressure of 2 kgf / cm ² for about 10 minutes to prepare a molded body in which the two non-woven fabrics are integrated. .

The molded body thus obtained was used in Example 1.
A bending test and a moisture absorption / desorption property test were conducted in the same manner as in, and the results are shown in Table 1. In addition, the load-displacement curve of the bending test is shown in FIG. 2, and as in Example 1, it showed a large amount of deformation without breaking.

[0035]

[Comparative Example 1] (Examples of the fiber-free) SiO ₂ content of 72% of volcanic vitreous clay (Biei clay Industries Ltd.) 78.6 parts by weight of SiO ₂ content of 72% of volcanic glassy balloon (Biei clay industry Manufactured by Taisetsu Balloon C) 11.4 parts by weight, and S
To 10.0 parts by weight of finely powdered silica (EFACO silica fume manufactured by Kinseimatic) having an iO ₂ content of 95%,
26.8 wt. A wet sand-like mixture was prepared by adding 37.3 parts by weight of an aqueous solution of NaOH having a concentration of 3% and mixing with a universal mixer.

1,145 g of this mixture was sprayed and laminated in a frame having an inner size of 30 × 30 cm made of Styrofoam with a uniform thickness, inserted into a hot press at 160 ° C. and a pressure of 10 kg was applied.
Thermal compression was performed at f / cm2 for 10 minutes. The molded body thus obtained was cut into a size of 30 × 200 mm and subjected to a bending test in the same manner as in Example 1, and the measurement results are shown in Table 2.
In addition, the load-displacement curve of the bending test is shown in FIG. 1, but after reaching the maximum point of the load, it was broken immediately and flexibility was not observed at all. Also, the test pieces fell apart.

[0037]

[Comparative Example 2] (when the amount of fibers is small) SiO ₂ content 7
90% by weight of 2% volcanic glassy clay (manufactured by Biei Shirato Kogyo Co., Ltd.) and 10 parts by weight of finely powdered silica having a SiO ₂ content of 95% (manufactured by Kinseimatic, EFACO silica fume) at 9.52 wt. A 105% by weight aqueous solution of NaOH having a concentration of 100% was added and mixed with a universal mixer to prepare a slurry.

This slurry was transferred to a square vat and 30 ×
Nonwoven mat cut to 30 cm (made by Toa Boshoku, polyester nonwoven CHINA 110MK, basis weight 110
g / m ² ) to impregnate the slurry, and then place it on a metal plate and squeeze out excess slurry by roller pressing to adjust the slurry impregnation amount to prepare a nonwoven mat containing about 452 g of the slurry.

The slurry-impregnated non-woven fabric mat was heated at 160 ° C.
It was put in the hot air dryer of No. 1 and pre-dried for about 40 minutes.
The water content of the slurry-impregnated nonwoven fabric was 25%. Two sheets of this pre-dried non-woven fabric were overlapped, sandwiched between release papers, placed in a heat press at 160 ° C., and heat-pressed at a pressure of 2 kgf / cm ² for about 10 minutes to prepare a molded body in which the two non-woven fabrics are integrated. .

The molded body thus obtained was used in Example 1.
A bending test and a moisture absorption / desorption property test were conducted in the same manner as in, and the results are shown in Table 1. In addition, the load-displacement curve of the bending test is shown in FIG. 1, and after the load reached the maximum point, the load dropped once but did not break.

[0041]

[0042]

[0043]

EFFECTS OF THE INVENTION The moisture absorptive and desorptive material of the present invention is prepared by adding an aqueous solution of alkali hydroxide at a specific mixing ratio to an amorphous silicate raw material to prepare a slurry, impregnating the nonwoven fabric base material, and then heat curing. It can be obtained with a simple operation. Moisture absorption and desorption,
It has excellent mechanical strength, especially flexibility, and is economical. Therefore, the moisture absorptive and desorptive material of the present invention can be suitably used for applications such as building interior materials, humidity control members and dehumidification members, and can also provide humidity control, dehumidification, and mold suppression effects.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // (C04B 28/26 C04B 16:06 Z 16:06) 111: 40 111: 40 (71) Applicant 501398721 Eiki Kogyo Co., Ltd. 8-1, Numanoha, Tomakomai City, Hokkaido, Japan (71) Applicant 596121747 Hiroyoshi Horikawa 11-chome, Kita-ku, Kita-ku, Sapporo, Hokkaido 1-chome, Kita Kaido R & D Center (71) Applicant 501398732 Takashi Itabashi, Hokkaido Sapporo, Kita-ku, Kita 19-jo Nishi 11-chome, Hokkaido Industrial Research Institute (72) Inventor Takuya Koga 7-92, Satomi-cho, Kitahiroshima-shi, Hokkaido (72) Inventor Yasuhiro Hirado 15-1 Shinko, Kisarazu-shi, Chiba Shin Nikka Iron Chemicals Co., Ltd. (72) Inventor Kosaku Ishikawa 136-426, Numanobata, Tomakomai City, Hokkaido 136-426 Oji Chemical Co., Ltd. (72) Eiji Maehara 136, Numanobata, Tomakomai City, Hokkaido 426 Oji Kagaku Kogyo Co., Ltd. (72) Inventor Takayuki Ara 601-8 Numanohata, Tomakomai City, Hokkaido Eki Kogyo Co., Ltd. (72) Inventor Keiichi Katsuse 11-chome, Kita-ku, Kita-ku, Sapporo, Hokkaido 11-Hokkaido Industrial Co., Ltd. (72) Inventor Hiroyoshi Horikawa, Hokkaido, Kita-ku, Kita-ku, Nishi 11-chome, Hokkaido 11-chome, Hokkaido Industrial Testing Station (72) Inventor, Takahisa Itabashi, Kita-ku, Sapporo, Hokkaido, Kita-ku, 11-chome, 11-chome Hokkaido Industrial Test Station, F Term (reference) 4G012 PA03 PA05 PA06 PA07 PA09 PA24 PB04 PC11 PE04 4G019 BA01 4G054 AA01 AA14 AC04 BA02 BA32 BB05

Claims (3)

[Claims] 1. A slurry comprising an amorphous silicate raw material and an aqueous solution of sodium hydroxide, wherein SiO ₂ / Na _{2 is used.}
After impregnating a non-woven fabric substrate with a molar ratio converted to O in the range of 5 to 20, heat treatment is performed to introduce a hydrophilic group into the silicate raw material, and at the same time, in the non-woven fabric, the silicate raw material is introduced. A moisture absorptive and desorptive porous molded article formed by bonding together. 2. A moisture absorptive and desorptive porous material characterized in that a nonwoven fabric substrate is impregnated with a slurry comprising an amorphous silicate raw material and an aqueous sodium hydroxide solution, and then heat-treated at 80 to 250 ° C. Method for manufacturing molded body. 3. A non-woven fabric substrate is impregnated with a slurry comprising an amorphous silicate raw material and an aqueous sodium hydroxide solution,
After preheating at ~ 250 ° C, 100 ~ 200
A method for producing a moisture absorptive and desorptive porous molded article, which comprises performing heat treatment under pressure with a hot press at ℃.